2524
Organometallics 1988, 7, 2524-2528
29.81, 23.13, 20.96, 20.81 (a anomer). The resonances assigned to the /3 anomer is 6 95.51. Anal. Calcd for B&1@32O,3: C, 44.85; H, 7.53; B, 25.23. Found C, 45.10; H, 7.42; B, 25.20. 1-[(2,3-Dideoxy-erytbro -hex-2-enopyranosyl)methy11- 1,2dicarbadodecahydroundecaborate(1-) ion (8). The potassium salt of this monoanion was prepared by a general degradation p r o c e d ~ e .3~(1.14 g, 2.95 mmol) was refluxed in ethanolic KOH (0.45 g, 0.5 M) for 20 h. The potassium salt was dissolved in water and converted to the tetramethylammonium salt by the addition of an excess of Me4NC1. This salt was recrystallized from water to give white plates (0.79 g, 73%). IR (Nujol mull): 3480-3460 (br m), 2525 (vs), 1088 (w), 1035 (s), 1020 (s br), 949 (m) cm-l. 'H NMR (acetone-d6): 6 5.88 (1H, br d, J = 10.2),5.68 (1H, br d, J = 10.2), 5.00 and 4.90 (1 H, 2 br s), 4.10-4.01 (2 H, m), 3.82-3.56 (6 H, m), 3.45 (12 H, s), 3.35 (1H, s), -2.6 (1H, br s). '% NMR (MeOH-d4):6 132.79,132.68,125.79, 125.76,92.96,92.31, 75.47, 74.65, 71.71, 71.68, 62.39,60.85,60.81, 54.36, 54.33, 54.30. llB NMR (acetone): 6 -9.91 (4 B, d, J = 135), -10.69 (1B, d), -11.01 (1B, d), -14.38 (1B, d, J = 167),-22.48 (2 B, d, J = 147), -32.82 (2 B, d, J = 121), -37.15 (2 B, d, J = 137). MS: cluster of peaks between mle 289 and 294, with most intense peak at mle 292. This m/e corresponds to 1oB111B8CgH2204. 1- [ (2,3-Dideoxy-a-~-erytbro - hex-2-enopyranosyl)methyl]-l,2-dicarba-closo-dodecaborane (9). K2C03(1.60 g, 11.6 mmol) was dissolved in 50 mL of 90% EtOH, with gentle heating. After the solution was cooled to room temperature, 2.01 g (5.20 "01) of 3 was added. This solution was stirred overnight and concentrated in vacuo. The solid thus produced was washed with 3 X 15 mL H20and recrystallized from chloroform (0.97 g,
62%): mp 143-144.5 O C . IR (Nujol mull): 3330-3274 (br s),3080 (m), 3060 (m), 2591-2569 (br s), 1409 (w), 1326 (m), 1305 (m), 1245 (w), 1180 (w), 1124 (m), 1095 (w), 1046 (s), 989 (m),984 (m), 959 (m) cm-'. 'H NMR (acetone-de): 6 5.97 (1H, br d, J = lO.l), 5.70 (1H, ddd, J = lO.l), 5.03 (1H, br s), 4.30 (1H, d, J = 11.4), 4.12 (1H, d, J = 11.4),4.01 (1H, m), 3.86-3.76 (2 H, m), 3.65-3.61 (2 H, m), 2.81 (2 H, br s, exchanges with DzO). l3C('H)NMR (DMSO-dd: 6 135.28,124.08,93.41,74.39,73.25,68.22,62.17,61.06, 60.64. Anal. Calcd for BloCgHz2O4:C, 35.77; H, 7.27; B, 35.77. Found: C, 35.31; H, 7.29; B, 35.42.
Acknowledgment. This research was supported by NIH Grant 1-R01-CA31753-06 and Battelle Columbus Laboratories Contract 85-468. We wish to thank Dr. A. Varadarajan for his insightful discussions and Nazim Jaffer and Dr. Jane Strouse for their assistance in the acquisition and interpretation of the NMR spectra. Registry NO.1,117162-37-5;CY-2, 117162-38-6;8-2,117162-39-7; CY-3,117162-40-0; 8-3, 117162-41-1; a-4, 117162-42-2; 0-4, 117183-74-1;CY-5, 117162-43-3;j3-5,117162-44-4;CY-6, 117162-45-5; 0-6,117162-46-6;CY-7, 117162-47-7;p-7,117162-48-8;8,91946-38-2; 9, 117162-49-9; H O C H ~ - O - C ~ B ~ ~ H19610-34-5; ~~-H, HOCH~CH~-O-C~B,~H 23835-95-2; ~~-H, HOCH2CH2-OC2BJIlo-CH3,20644-51-3; HO(CH~)~-O-C~B~&~~-H, 23835-93-0; HO(CH2)3-o-C2BloHlo-CH3, 17815-32-6; l-o-acetyl-2,3,5-tri-obenzoyl-@-D-ribofuranose, 6974-32-9; 3,4-di-O-acetyl-D-xylal, 3152-43-0; tri-o-acetyl-D-gluca1,2873-29-2.
Transition-Metal-Substituted Silanes. Hydrosilylation of Phenylacetylene Using [(q5-C5H5)Fe(C0j2SiPh2H] and [ (q5-C,H,SiPh2H)Fe(CO)2R] (R = Me, SiMe,)' Keith H. Pannell," James M. Rozell, Jauching Lii, and Shu-Yuan Tien-Mayr Department of Chemistry, The Universiw of Texas at El Paso, El Paso, Texas 79968-05 13 Received April 13, 1988
The complex [ (q5-C$IS)Fe(CO)&3iPhzH](FpSiPhzH, I) has been synthesized and characterized. Treatment of I with i-Pr2NLi (LDA) followed by Me1 or Me3SiC1 produces the silyl migration products [(q5C5H4SiPhzH)Fe(CO)zR](R = Me (IIa), SiMe3 (IIb)). Addition of the Si-H bonds to phenylacetylene using chloroplatinic acid yields exceptionally high yields of the appropriate a products. The hydrosilylation products of I may be transformed into those of I1 by treatment with LDA followed by Me1 or Me3SiC1. The trans-@-silylstyrenehydrosilylation products were synthesized independently by the reaction of [(q5-C5H4R)Fe(C0)z]-Na+ (R = H, SiMe3) with trans-Ph2Si(C1)CH=CHPh.
Introduction Transition-metal complexes containing a Si-H bond are relatively uncommon compared to those with halogen, alkyl, or aryl groups bonded to silicon; however, those complexes that are reported exhibit much unusual chemi s t ~ ~ . For ~ - ~example, the silicon-hydrogen bond of [ (q5-C5H5)Fe(CO)zSiMezH](FpSiMe,H), exhibits a low
Si-H stretching frequency and is readily transformed into a silicon-chlorine bond upon treatment with CC14;5 bridging metal-hydrogen-silicon systems are and (dimethylsily1)methyl groups readily rearrange to trimethylsilyl groups, e.g. [ (#-CSH5)M(CO)nCHzSiMezH] [ (q5-C5H5)M(CO)nSiMe3].8*9 Given the interesting chemistry it is surprising that the most studied reaction of organosilicon hydrogen bonds, namely, hydrosilylation, has
(1) Part 18. Organometalloidal Derivatives of the Transition Metals. For part 17 see; Parkanyi, L.; Pannell, K. H.; Hernandez, C. J. Organomet. Chem. 1988,347, 295. (2) Aylett, B. J. Adv. Znorg. Chem. Radiochem. 1982, 25, 1. (3) Pannell, K.H.Silicon Compounds: Register and Review, Anderson, R., Arkles, B., Larson, G . L. Eds.; Petrarch Systems Inc.: Bristol, PA, 1987; pp 32-39. (4) Cundy, C. S.; Kingston, B. M.; Lappert, M. F. Adv. Organomet. Chem. 1973,11, 253.
(5) King, R. B.; Pannell, K. H.; Ishaq, M.; Bennett, C. R. J . Organomet. Chem. 1969, 19, 327. (6) Schubert, U.;Muller, J.; Alt, H. G. Organometallics 1987, 6, 469. (7) Schubert, U.; Scholz, G.; Muller, J.; Ackermann, K.; Worle, B.; Stansfield, R. F. D. J . Organomet. Chem. 1986, 306, 303. (8) Pannell, K. H.J. Organomet. Chem. 1970,21,17; Transition Met. Chem. (Weinheim, Ger.) 1975/1976, 1, 36. (9) Lewis, C.; Wrighton, M. S. J . Am. Chem. SOC.1983, 105, 1067.
-
0276-7333/88/2307-2524$01.50/0 0 1988 American Chemical Society
Transition-Metal-Substituted Silanes
Organometallics, Vol. 7,No. 12, 1988 2525
Table I. Spectral Data of Complexes' (~s-C5H6)Fe(C0)zSiPhzH (I) (q5-CsH4(Ph)C=CHzFe(CO)zSiMe3 (Vb) 13C 7.4 (SiMe3), 86.8,87.0,90.0 (C6H4),127.0,127.5,127.9,128.2, 13C 84.2 (CsHs),127.7,128.4, 134.5,141.3 (Ph),214.3 (CO) 130.0,133.7,133.8,136.1,143.5,146.6 (Ph),214.9 (CO) 'H 4.71 (C,H,), 5.67 (SiH),7.36,7.69 (Ph) 'H 0.40 (%Me3), 4.39 (m),4.59 (m,CsH4), 5.94 (d,J = 2.5 Hz), 2BSi 27.1 6.37 (d, J = 2.5 Hz,C=CHz), 7.3-7.8 (Ph) v(C0) 2008, 1956,v(SiH) 2085 i%' -17.0 (C5H4Si), 41.9 (FeSi) (.?s-C6H4SiPhzH)Fe(CO)zMe (Ha) v(C0) 1997,1942 -22.7 (Me), 80.0, 87.8, 94.5 (C&), 128.1, 130.1, 132.9, 135.4 13C (Ph),216.7 (CO) (t$C6H4SiPhz-trans-CH=CHPh)Fe(CO)zMe (VIa) 13C -22.9 (Me),83.0,88.7,94.0 (CbH,), 121.8,126.9,127.6,128.0, lH 0.20 (Me),4.89 (m,C6H4),5.48 (8, SiH),7.47,7.68 (Ph) 128.6,130.0,133.9,135.7,137.8,149.4 (Ph),217.1 (CO) %i -21.0 'H 0.11 (SiMeJ,4.87 (m,C5H4),7.0-7.7 (Ph) v(C0) 2014, 1958,v(SiH) 2143 -19.0 ($-CsH4SiPhzH)Fe(CO)zSiMe3 (IIb) v(C0) 2014,1957 7.6 (SiMe3), 83.8, 87.2, 90.0 (C,H,), 128.1, 130.2, 132.6, 13C (s5-C5H4SiPh2-trans-CH=CHPh)Fe(C0)2SiMe3 (VIb) 135.5 (Ph),215 (CO) 86.6,87.2,98.9 (C5H4), 122.1,126.8,127.6,128.0, 0.43 (SiMe3),4.72 (m,C5H4),5.49 (s, SiH),7.44,7.70 (Ph) 13C 7.6 (SiMe3), 'H 128.6,129.9,133.8,135.8,137.8,149.2 (Ph),215.2 (CO) "si -21.2 (C6H4Si),42.0 (FeSi) v(C0) 1997,1944,v(SiH) 2140 'H 0.41 (SiMe3),4.69 (m),4.75 (m,C6H4),7.4-7.7 (Ph) %i -19.2 (C5H4Si), 41.6 (FeSi) (~S-CsH6)Fe(C0)zSiPhz(Ph)C=CHz (111) v(C0) 1995,1940 84.5 (CbHs), 126.2, 127.5, 127.7, 127.8, 128.2, 130.1, 135.3, "C ($-C5H4SiMe3)Fe(CO)zSiPhzH(VII) 142.2,146.2,154.0 (Ph,CHZ)), 215.3 (CO) 'H 4.40 (C,H6),5.64 (d,J = 3.0 Hz),6.01 (d, J = 3.0 Hz,CHz), 13C 0.1 (SiMe,),87.8,89.9,92.1 (C&), 128.1, 128.7,134.9,141.9 (Ph),215 (CO) 7.1-7.6 (Ph) 'H 0.49 (SiMe3),4.67,4.88 (C5H4), 5.91 (SiH),7.5-7.9 (Ph) %i 37.0 29si -4.0 (C6H4Si),27.4 (FeSi) v(C0) 2008,1956 v(C0) 2002, 1951,v(SiH) 2080 (~s-CsH,)Fe(CO)zSiPhz-trans-CH=CHPh (IV) (~5-CsH4SiMes)Fe(CO)zSiPhz(Ph)C=CHz (VIII) 13C 84.5 (CSHs),126.6,127.6,127.8,128.3,128.4,131.9,135.0, 13C -0.6 (SiMe3),88.3,88.8,93.0 (C6H4),126.2,127.5,127.8, 138.6,142.0,143.7,215 (CO) 127.9,128.2,130.2,135.4,142.4,146.3,154.2 (Ph),215.6 lH 4.68 (C,H,), 6.76 (d,J = 18.7 Hz), 7.09 (d,J = 18.7 Hz, CH-CH), 7.3-7.6 (Ph) (CO) 'H 0.27 (SiMeJ,4.33 (m),4.40 (m,C&4), 5.74 (d,J = 3.0 Hz), %Si 31.6 6.11 (d,J = 3.0 Hz),7.2-7.7,216.6 (CO) v(C0) 2006, 1954 29si -4.3 (C6H4Si),36.5 (FeSi) (q6-C5H4(Ph)C=CHz)Fe(C0)zMe (Va) v(C0) 2002, 1950 13C -22.7 (Me),83.1,89.9,92.9 (C6H4),127.0, 127.5,128.0, (~6-C5H4SiMe3)Fe(CO)zSiPhz-trans-CH=CHPh (1x1 128.3,130.0,133.6,133.9,136.1,143.6,146.4 (Ph),216.7 13C -0.4 (&Me3), 88.2,89.3,92.3 (C&), 126.6,127.6,127.8, GO) 128.3,124.4,132.1,135.1,138.7,142.1,143.7 (Ph),215.3 0.0 (Me),4.45,4.70 (C6H4), 5.84 (d,J = 2.1 Hz),6.28 (d,J lH = 2.1 Hz), 7.2-7.7 (Ph) (CO) %i -16.4 'H 0.32 (SiMe3), 4.44 (m),4.75 (m,C5H4),7.3-7.7 (Ph) v(C0) 2014, 1957 29Si -4.2 (C5H4Si), 30.8 (FeSi) v(C0) 2000,1949
'"Si, 13C,and 'H NMR spectra (chemicalshifts in ppm) were recorded in CDC13with the exception of the %i VIb, VIII, and IX which were recorded in CEDE. IR spectra were recorded in hexane. not been reported for transition-metal SiH complexes. It is the purpose of this paper to report the complex (q5C6H6)Fe(C0)2SiPh2H(I) and the chloroplatinic acid catalyzed addition of I and its migrated products 11, (q5C6H4SiPh2H)Fe(CO)2R(R = Me, SiMeJ, to phenylacetylene.
Results The synthesis of the title complex FpSiPhzH (I) was accomplished by reaction 1.
+
-
[(q5-C5H6)Fe(CO)2]-Na+ PhzSiHCl (q5-C5H5)Fe(CO)zSiPh2H (1) I In contrast to the related dimethylsilyl complex [(q5C6H6)Fe(CO)&MezH,5]complex I may be readily handled in air and purified by column chromatography and recrystallization. Despite a Si-H stretching frequency a t 2085 cm-' (hexane), cf. Ph3SiH at 2131 cm-', I is thermally stable and treatment in refluxing toluene for 24 h does not produce a chemical reaction. The complex is photochemically active under variety of conditions, and such chemistry will be the subject of a future publication. Treatment of I with lithium diisopropylamide (LDA) resulted in initial deprotonation of the cyclopentadienyl ring as in the case for the trialkyl-/triarylsilane complexes of the iron As with previous studies, silyl
spectra of complexes I, Vb,
group migration occurs to produce a ferrate salt, in this The salt was trapped case [ (q5-CsHrSiPh2H)Fe(C0)2]-Li+. using either Me1 or Me3SiC1to produce complexes IIa and IIb, respectively, in which the Si-H functionality has been
LDA/RX
(q5-C5H5)Fe(C0)zSiPhzH (q5-C6H4SiPh2H)Fe(CO)zR(2) I1 RX = Me1 (IIa), Me3SiC1 (IIb) successfully transferred from the Fe atom to the cyclopentadienyl ring. This is the fist example of the migration of a silyl group with a useful functional group in such reactions. It is of interest that the Si-H stretching frequency in the intermediate ferrate salt and the resulting complexes IIa and IIb is at 2143 cm-' as compared to the value of 2085 cm-' in the starting complex. Clearly the electron density in the ferrate salt is quite localized upon the Fe atom, and both the salt and the complexes 11behave as species very similar to PhsSiH in terms of the stretching (10) Thum, G.; Ries, W.; Greissinger, D.; Malisch, W. J . Oganomet. Chem. 1983,252, C67. (11) Berryhill, S. R.; Clevenger, G. L.; Burdurli, P. Yu. O g a n o metallics 1986, 4,1509. (12)Pannell, K.H.;Cervantes, J.; Hernandez, C.; Vincenti, S. Organometallics 1986,5 1056. (13) Pannell, K. H.; Vincenti, S.; Scott 111, R. Ogranometallics 1987, 6,
1593.
2526 Organometallics, Vol. 7, No. 12, 1988
Pannell et al.
Table 11. New Comdexes: Analytical Data I IIa IIb I11 IV Va Vb VIa VIb VI1 VI11 IX
found (calcd) 63.16 (63.34) 63.51 (64.18) 61.11 (61.10) 69.85 (70.13) 70.14 (70.13) 70.56 (70.59) 67.36 (67.41) 70.56 (70.59)
found (calcd) 4.57 (4.48) 4.64 (4.85) 5.70 (5.59) 4.98 (4.80) 4.76 (4.80) 5.38 (5.08) 5.72 (5.62) 5.18 (5.08)
66.05 (67.41) 66.87 (66.40)
5.60 (5.62) 5.82 (5.66)
mp, "C 91 121 133 81 110 82 102 75
aComplex VI1 is an air- and temperature-sensitive oil which cannot be purified by column chromatography or recrystallization. All spectral and chemical properties are consistent with the structure, but attempts to obtain satisfactory elemental analysis were unsuccessful.
Table 111. Redoselectivity of SiH Addition to PhC=CH % products transSiCH=CHSi(Ph)complex Ph C=CH2 (#-C5H5)Fe(CO)2SiPhzH 18 82 ( $-C5H4SiPh2H)Fe(CO)zMe 30 70 ($-C5H4SiPh2H)Fe(CO)2SiMe3 67 33 ( Q ~ - C ~ H ~ S ~ M ~ ~ ) F ~ ( C O ) ~32S ~ P ~ , H 68
frequency of the Si-H bond. The spectral and analytical properties of the new complexes are recorded in Tables I and 11and conform with the described structures. Hydrosilylation reactions of I with phenylacetylene were attempted with several different catalysts, i.e. platinum on carbon, [Rh(dipho~)~(norbornadiene)]+PF,-, and chloroplatinic acid. Of these only chloroplatinic acid proved effective and even then elevated temperatures were required; therefore all hydrosilylation reactions were performed in refluxing toluene. The product distribution from the hydrosilylation of phenylacetylene by I is recorded in Table 111. The data indicate that of the three possible compounds that may be formed, a-silylstyrene, trans-P-silylstyrene, and cis-0-silylstyrene,the predominant isomer formed was the a-silylstyrene (82%),with 18% of the trans-/3-styrene and a trace of the cis-&styrene. (?5-C5H5)Fe(C0)2S~Ph2H + PhCECH
-
(q5-C5H4S~Ph2H)Fe(CO)2R + PhC-CH
HpPtClg
FpPhpSi
FpPh2Si
\ Ph?=c\
showed that the regioselectivity of addition changed as the degree of phenyl substitution changed, whereas Ph3SiH yielded an p:a product ratio of 95:5; this progressively decreased upon Me substitution of P h to a ratio of 72:28 for Me2PhSiH.20 In general, addition of silanes to acetylenes leads to predominantly trans-p-olefins and a study by Hill and Nile reported that use of a rhodium carbene catalyst resulted in the sole formation of @-addition pr0duck3.l~Directly related to our study is the report that cymantrenylmethylphenylsilane, (q5-C5H,SiPh(Me)H)MII(CO)~,adds to phenylacetylene to yield a ratio of 73:27 trans-p:a addition.21 To determine if the uniquely high yields of a-product I11 obtained by using I were due to the presence of the Si-Fe bond, we also performed the identical hydrosilylation reaction with the migrated complexes IIa and IIb. The reaction with IIa yielded a product distribution almost identical with that with I, clearly indicating that the abnormally high a-styrene formation was not due to the presence of a direct metal-silicon bond. Increasing the steric bulk of the complex by having a trimethylsilyl group attached to the Fe atom, IIb, did reduce the amount of a-product when compared to the results from complexes I and IIa, but even in this case the 33% yield of a-silylstyrene is still somewhat high for such a reaction when compared to a 5% or 22% yield for Ph3SiH and Ph,MeSiH, respectively.
\
/H
111 ( 8 2 % )
H
+
/H
/"=%
H
HePtCIe
/
H
(3)
Ph
I V (18%)
Compared to the hydrosilylation of olefins, reports on the addition of silanes to acetylenes are relatively It has been established that the hydrosilylation of diphenylacetylene by optically active NpPhMeSiH resulted in a cis addition with retention of configuration at silicon." A recent study of the monoaddition of PhnMe3-,SiH to phenylacetylene catalyzed by chloroplatinic acid salts (14) Benkeser, R. A.; Burrows, M. L.; Nelson, L. E.; Swisher, J. V. J. Am. Chem. SOC.1961,83,4385. (15)Hill, J. E.;Nile, T. A. J. Organomet. Chem. 1977, 137, 293. (16)Green, M.;Spencer, J. L.; Stone, F. G. A.; Tsipis, C. A. J.Chem. SOC.Dalton Trans. 1977, 1525. (17)Brook, A. G.; Pannell, K. H.; Anderson, D. J. Am. Chem. SOC. 1968,90, 4375. (18)Ojima, I.; Kumagai, M.; Nagai, Y. J.Organomet. Chem. 1974,66, C14.
(19)Lukevics, E.; Sturkovich, R. Ya.;Pudova, 0. A. J. Organomet. Chem. 1986,292, 151. (20) Iovel, I . G.; Goldberg, Y. Sh.; Shymanska, M. V.; Lukevics, E. Organometallics 1987, 6,1410.
Ph
/
\
H
Va: R -Me ( 7 0 % ) b : R = MeaSi (33%) RFe(C0)z(?5-C5H4(Phz) SI; \
I
7=c\
H.
(4)
Ph
V I a : R = Me ( 3 0 % ) b: R = Me,Si ( 6 7 % )
These results indicate that the presence of the SiPh2H group in the coordination sphere of a [(v~-C,H,R)F~(CO)~] group results in a generally higher a-addition in the hydrosilylation reaction. Also, steric factors play a role in reducing the extent of this unusual regioselectivity since the greater steric bulk of the overall complex is expected to yield more of the @product IV as observed, i.e. IIa vs IIb. (21)Asatiani, L. P.; El-Agami, A. A. Zh.Obshch. Khim. 1980,50,1584.
Organometallics, Vol. 7, No. 12, 1988 2527
Transition-Metal-Substituted Silanes
to room temperature. At this time the solvent was removed and the resulting thick gum extracted into 100 mL of a 4060 methylene chloride/hexane solution and filtered. The filtrate was concenLDA trated to 10 mL and this solution placed upon a silica gel column, (T~-C~H~)F~(CO)~S~M~~ 2.5 X 20 cm. Elution with a 25:75 methylene chloride/hexane Ph2Si(H)CI solvent mixture yielded a yellow band that upon collection, [( T ~ - C ~ H , S ~ M ~ ~ ) F ~ ( C O ) ~ ] - L ~ + ( T ~ - C ~ H ~ S ~ M ~ ~ ) F ~((5 C ) O ) concentration, ~ S ~ P ~ ~ Hand recrystallization from a 2 0 8 0 methylene chloride/hexane solution yielded 5.1 g (51%) of the title complex. Treatment of I with Lithium Diisopropylamide. To 30 the same hydrosilylation reaction to determine if the extra mL of a cooled (0 "C) THF solution of I (2.0 g, 5.6 mmol) was steric bulk of the trimethylsilyl group was equally imadded dropwise a 10-mL solution of LDA (5.6 mmol). Monitoring portant when placed upon the cyclopentadienyl ring while by infrared spectroscopy indicated that after 40 min the correthe SiPh2H group was bonded to the Fe atom, i.e. intersponding ferrate salt [(?5-C5H4SiPhzH)Fe(CO)z]-Li+ had changing the relative positions of the two Si groups (eq 6). f ~ r m e d To . ~this ~ ~solution ~ ~ was added 0.7 mL (11.3 mmol) of MeI, and the solution was stirred for 30 min. The solvent was HtPtCIe LMPhzSIH + P h C E C H removed under vacuum and the residue extracted with a 40:60 methylene chloride/hexane solvent mixture and purified by LMPh2Si LMPh2Si chromatography on a silica gel column, 2.5 x 20 cm, made up in \ IH( 6 ) \ /H+ hexane. Elution with an 8515 hexane/methylene chloride solvent mixture produced a yellow band that was collected and after H Ph Ph H removal of the solvents yielded 1.5 g (72%) of IIa as an oil. V I 1 1 (68%) I X (32%) Reaction of the intermediate ferrate salt with Me3SiCl was LM = ( , ~ - C , H , S I M ~ ~ ) F ~ ( C O ) * performed by a reverse addition procedure, i.e. addition of the ferrate salt to Me,SiCl, and produced a 71% yield of IIb. Normal In total, these results, all of which are tabulated in Table addition was complicated via the formation of secondary mi111, indicate that the effect of the Me3& group upon the grations due to the presence of excess LDA upon formation of regioselectivity of hydrosilylation of the SiPh2H moiety IIb. Hydrosilylation Reactions. In a typical reaction, a 100-mL is limited to the situation when it is bonded to the Fe atom. round-bottomed flask equipped with a reflux condenser and This suggests that there may be some direct interaction magnetic stirring bar was charged with 2.20 g (6.11 mmol) of I between the Pt catalyst and the Fe coordination sphere and 1.3 mL (11.8 mmol) of phenylacetylene in 20 mL of toluene. during the catalytic cycle. The precise nature of this inTo this mixture was added 2.0 mg of HzPtC&.The solution was teraction is unclear but is currently under investigation. refluxed for 1 h after which time infrared monitoring of the Si-H The hydrosilylation products were separated by column stretching frequency showed that the reaction was complete. The chromatography and fully characterized by the appropriate solvent was removed under reduced pressure to yield a thick gum spectroscopic techniques. These data are recorded in that was extracted into 10 mL of a 4 0 6 0 methylene chloride/ Table I. As expected, the 29SiNMR data for the various hexane solvent mixture. This was placed upon a silica gel column, complexes with a direct Si-Fe bond, I, IIb, 111, IV,Vb,VIb, 2.5 X 20 cm, eluted with a 30:70 mixture of the same solvents to collect all the hydrosilylation products. This procedure resulted VII, VIII, and IX, exhibit low-field chemical shifts of apin the recovery of a pale yellow semisolid (2.1 g, 4.52 mmol, 74%) proximately 35 ppm for these Si atoms when compared to that was shown by NMR spectrcjscopyto comprise of a 8218 ratio the SiMe analogues, e.g. FpSiPhzH vs MeSiPh,H.22 of (q5-C5H6)Fe(CO)zSiPh2(Ph)C=CHz (111) and trans-($Silicon atoms attached directly to the cyclopentadienyl ring C5H5)Fe(CO)zSiPh2CH=CHPh (IV). This procedure resulted exhibit slightly high field shifts, 3.5 ppm, as noted in in essentially the same ratio of products as determined by NMR previous studies.12 Such shifts for the two types of silicon analysis of the crude gum obtained prior to chromatography, but atom greatly facilitate complete identification. with significantly superior resolution. High-pressure liquid Further product characterization was provided by inchromatographic analysis of this crude mixture indicated a trace dependent synthesis. Complexes IV and M were obtained amount ( 1 % ) of a material that may be the related ci~-(7~C5H5)Fe(CO)2SiPh2CH=CHPh. from the reactions of the appropriate ferrate salts with This crude reaction product was rechromatographed, eluted trans-PhzCISiCH=CHPh (eq 7). with an 85:15 hexane/methylene chloride solvent mixture, and [ (~5-C5H4R)Fe(CO)z]+ trans-Ph2C1SiCH=CHPh the two major products were separated, complex 111, the a-silylstyrene eluting first (1.6 g 3.4 mmol, 56%), and IV, the ($-C6H4R)Fe(CO)2-trans-SiPhzCH=CHPh (7) trans-0-silylstyrene eluting second (0.3 g, 0.6 mmol, 10%). R = H (IV), SiMe3 (IX) All other hydrosilylations were performed by using the same procedure for determining product distributions and purification if required. Experimental Section Synthesis of VIb from IV by LDA Treatment. To a soAll manipulations were performed in Nz atmospheres by using lution of 0.5 g (1.1 mmol) of IV in 10 mL of THF was added an dry oxygen-free solvents. Starting chlorosilaneswere purchased equivalent of LDA in 2 mL of THF, and the mixture was stirred from Petrarch Systems Inc., and [ ($-C5H5)Fe(CO)z]zwas purfor 30 min at 0 "C. At this time infrared monitoring indicated chased from Strem Chemicals. the presence of the ferrate salt [ (v5-C5H4SiPh2-trans-CH= NMR spectra were recorded on a Bruker NR 200 MHz mulCHPh)Fe(CO)z]-Li+.This salt was quenched with an excess of tinuclear spectrometer and IR spectra on a Perkin-Elmer 580B MeaSiCland stirred for 30 min. Removal of the solvents, chrospectrometer. Elemental analyses were performed by Galbraith matography on silica gel, 2.5 X 20 cm column, made up in hexane Laboratories Inc., Knoxville, TN. and eluted with 2080 methylene chloride/hexane solvent mixture, Typical reactions are described below, and all spectral and and final recrystallizationfrom hexane yielded 0.39 g (0.73 mmol, analytical data are provided in the tables. 66%) of VIb. Synthesis of (q6-C5H5)Fe(CO)2SiPhzH (I). To 100 mL of an analogous fashion we synthesized VIa in 55% yield and a cooled (0 "C) THF solution of [ ( I ~ - C ~ ~ ) F ~ ( C ~obtained ) , ] - N ~ + VaInand Vb from I11 (65% and 57% yields, respectively). from 5.0 g (14.1 mmol) of [(q5-C5H5)Fe(CO)2]2 was added dropwise Independent S y n t h e s i s of (q5-C5H4SiMe3)Fe20 mL of a THF solution of PhzSiHCl (6.2 g, 28.2 mmol). The (CO)zSiPhz-trans-CH=CHPh (IX). Into a three-necked flask solution was stirred for 1 h and the temperature permitted to rise was charged 0.57 g (2.27 mmol) of ( I ~ - C ~ H , ) F ~ ( C O )in~ 10 S~M~~ The extent of this steric role was studied by synthesizing
( T ~ - C ~ H ~ S ~ M ~ ~ ) F (VII) ~ ( C(eq O )5)~and S ~performing P~~H
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-
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(22) Pannell, K. H.; Bassindale, A. R. J.Organomet. Chem. 1982,229, 1.
(23) Pannell, K. H.; Jackson, D. A. J. Am. Chem. SOC. 1976,98,4443. (24) Nitay,M.; Rosenblum, M. J.Organomet. Chem. 1977,136, C23.
Organometallics 1988, 7, 2528-2534
2528
mL of THF. To this cooled solution (0 "C) was added an equivalent of LDA in THF, and the reaction mixture was stirred for 40 min at which time was added an equivalent of trans(Cl)SiPhzCH=CHPhdissolved in 10 mL of THF. The solution was permitted to warm to room temperature and stirred for 30 min. After removal of the solvents and extraction with a 40:60 methylene chloride/hexane solvent mixture, the crude material was placed on a silica gel column, 2.5 X 20 cm made up in hexane, and eluted with a 20:80 methylene chloride/hexane solvent mixture. The resulting material was recrystallized from hexane to yield 0.86 g (1.61 mmol, 71%) of the title compound. Independent Synthesis of (86-C6H6)Fe(CO)zSiPhz-~r~nS-
CH=CHPh (IV). To a solution of [(?6-C6HdFe(C0)z]-Na+
prepared from 1.6 g (9.04 mmol) of [(~6-C6Hs)Fe(Co)z]g in THF was added an equivalent of (C1)SiPhz-tram-CH=CHPh. The mixture was stirred for 30 min, and workup as above yielded IV (1.5 g, 3.2 mmol, 35%).
Acknowledgment. This research has been supported by a Texas Advanced Techolofl Research Award and the Robert A* Welch Foundation, Houston, TX. Financial support by the Dow Corning Corp. is gratefully acknowledged.
Synthesis and Characterization of Rhodium( I ) Amino-Olefin Complexes Marie E. Krafft" and Lawrence J. Wilson Department of Chemistry, Florida State Universi?v, Tallahassee, Florida 32306-3006
Kay D. Onan Department of Chemlstty, Northeastern University, Boston, Massachusetts 02 1 15 Received April 15, 1988
The syntheses of [(CH2CR1CHzCH2NR2R3)RhClL complexes (R,= CHS,H, R2 = n-Bu, Rs= H;R1 = CHS,H, Rz = R3= CHS,L = CO or dimer; 19-32 and 38-43) are reported. The complexes are prepared by the reaction of unsaturated amines with bis(fi-chloro)tetracarbonyldirhodium(I)(3) or bis(pch1oro)tetrakis(ethylene)dirhodium(I) (4) at ambient temperature. Compound 19, [N-(trans-&pentenyl)n-butylamine]carbonylrhodium(I)chloride, crystallized in the monoclinic space group ml/c with cell dimensions a = 17.699 (5), b = 8.442 (l), and c = 20.119 ( 5 ) A, and L? = 120.19 ( 2 ) O .
Introduction As part of our research program directed toward the regioselective functionalization of simple olefins by prior coordination to transition metals,' we found the need for Rh(1) complexes containing bidentate olefinic ligands. Numerous Rh(1) complexes with bidentate ligands are known;2 however, none proved suitable for our purpose. Diolefin complexes2would not be useful because of the question of regiocontrol during alkene functionalization if an unsymmetrical diolefin was utilized. We were interested in complexes, such as 1, which incorporated bidentate, monoolefin ligands where a heteroatom was tethered to the olefin by a carbon chain to yield a chelated ligand. Olefinic phosphine^^^^ have been shown to give rise to Rh(1) complexes (e.g. 2) containing bidentate ligand^.^ (1) Krafft, M. E. J. Am. Chem. SOC.1988, 110, 968. Krafft, M. E. Tetrahedron Lett. 1988, 29, 999. (2) Dickson, R. S. Organometallic Chemistry of Rhodium and Iridium; Academic: London, 1983. Hughes, R. P. In Comprehensioe Organometallic Chemistry; Wilkinson, G . Ed.; Pergamon: Oxford, 1982; VO~. 5, pp 277-540. (3) Heifkamp, S.; Stufkens, D.; Vrieze, K. J. Organomet. Chem. 1978, 152, 347. Clark, P. W.: Hartwell, G. E. J. Organomet. Chem. 1978,96, 451. (4) Clark, P. W.; Hartwell, G. E. J. Organomet. Chem. 1975,102,387. Clark, P. W.; Hanisch, P.; Jones, A. J . Inorg. Chem. 1979, 18, 2067. Bennett, M. A,; Johnson, R. N.; Tomkins, I. B. J. Organomet. Chem. 1976,118,205. Bennett, M. A,; Johnson, R. N.; Tomkins, I. B. J. Organomet. Chem. 1977, 133, 231. Curtis, J. L. S.; Hartwell, G. E. J. Organomet. Chem. 1974, BO, 119.
1
2
However, subsequent synthetic utility of the phosphine ligand after olefin functionalization was questionable. While allylic amines have been shown to give rise to polymeric materials6a*bupon reaction with bis(pch1oro)tetracarbonyldirhodium(1) (3), we found that homoallylic and bishomoallylic amines reacted with both 3 and bis(p-chloro)tetrakis(ethylene)dirhodium(I) (4) to give rise to a series of new complexes containing bidentate olefinic ligands.& We now report our results on the synthesis and characterization of these new Rh(1) complexes. (5) For discueaions on the mechanism of ligand exchange, see: Atwood, J. D. Inorganic and Organometallic Reaction Mechanism; Brooks/Cole: Monterey, CA, 1985. Reference 6b. Collman, J. P.; Hegedus, L. S.; Norton, J. R.; Finke, R. G. Principles and Applications of Orgamtransition Metal Chemistry; University Science B o o k Mill Valley, CA, 1987. Heck, R. F. Organotransition Metal Chemistry, A Mechanistic Approach; Academic: New York, 1974. (6) (a) Fougeroux, P.; Denise, B.; Bonnaire, R.; Pannetier, G. J. Organomet. Chem. 1973,60,376. (b) Maisonnat, A.; Kalck, P.; Poilblanc, R. Inorg. Chem. 1974,13,2996. (c) Ibe@ has shown that N-allyhiline reacts with 4 in THF to give a bidentate olefinic amine complex. We found that reaction of allylamine with 4 in CHzClz gave rise to an uncharacterizable orange solid. (d) Aresta, M.; Quaranta, E.; Treglia, S.; Ibers, J. A. Organometallics 1988, 7, 577.
0276-7333/88/2307-2528$01.50/0 0 1988 American Chemical Society
